A novel broadband circular antenna hybrid front-end device and its corresponding spatial azimuth angle measurement method

Abstract

The present invention discloses a novel broadband circular antenna hybrid front-end device and a corresponding spatial azimuth angle measurement method, wherein the device comprises a circular antenna array, an analog phase shifting network, a radio frequency link and a digital baseband processor; each array element in the circular antenna array is connected to each phase shifter in the analog phase shifting network in a fully connected manner; the analog phase shifting network is connected to the digital baseband processor via the radio frequency link. The design of the radio frequency link of the device of the present invention is independent of the configuration of the communication system, is applicable to a variety of communication scenarios, simplifies the calculation cost of the system, and the azimuth angle measurement method directly performs singular value decomposition on the collected signal data set, does not require related operations, and has a low amount of calculation.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and in particular relates to a novel broadband circular antenna hybrid front-end device and a corresponding spatial azimuth angle measurement method thereof. Background Art

[0002] Broadband communication systems, such as millimeter wave communication (30-300GHz), have abundant frequency band resources. Compared with traditional microwave communication working below 6Ghz, millimeter wave communication can provide more than 200 times the bandwidth, which can greatly improve the transmission rate of the network.

[0003] Traditional antenna front ends are mostly designed based on narrowband communication. Due to the large frequency variation range of broadband communication systems, large-scale changes in system frequency will cause the direction of traditional antenna beams to change significantly, resulting in beam shift effects, causing channel dispersion in spatial angles and reducing system performance. Therefore, traditional antennas used in broadband communication systems have serious beam shift problems caused by frequency changes.

[0004] Compared with linear and square arrays, circular antenna arrays have the advantages of strong robustness, simple beam control, and the ability to provide full azimuth. However, the azimuth measurement of traditional circular array antennas is complicated due to the nonlinear phase relationship between the array response functions. At the same time, when using large-scale antenna arrays, the large number of antennas and the large amount of calculation limit their use in actual communication systems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art, provide a new broadband circular antenna hybrid front-end device and its corresponding spatial azimuth angle measurement method, propose a low-complexity large-scale circular antenna hybrid front-end device suitable for broadband communication systems, and use the recursive characteristics of the phase between the data streams output by the hybrid front-end to quickly measure the spatial azimuth angle. The device requires fewer RF links and has low hardware costs. The azimuth angle estimation does not require related operations and global searches of the space, and is simple to implement with low complexity.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0007] A new broadband circular antenna hybrid front-end device, including a circular antenna array, an analog phase-shifting network, a radio frequency link, and a digital baseband processor;

[0008] Each array element in the circular antenna array is connected to each phase shifter in the analog phase shift network in a fully connected manner;

[0009] The analog phase shift network is connected to the digital baseband processor via the radio frequency link.

[0010] To optimize the above technical solutions, the specific measures taken also include:

[0011] The above-mentioned analog phase shift network is a network with a dimension of P′×N, including a phase shifter and an adder; wherein N is the number of array elements of the circular antenna array, P′=(2P+1), is the number of the RF links, and P is the maximum dimension of the Bessel space.

[0012] The above-mentioned phase shifter is connected to each array element in the circular antenna array via a fully connected manner, and the connection method is based on an asymmetric discrete Fourier transform design, which is specifically expressed as follows:

[0013]

[0014] Wherein p = -P, -P+1, ..., P, and n = 1, 2, ..., N, is the number of elements of the circular antenna array.

[0015] The number of the above-mentioned radio frequency links is determined by using the generalized convergence characteristics of the Bessel function, as follows:

[0016] 1) Assume that a(θ l ) is the array response function of the circular antenna array, and the array response function expression of the nth array element is:

[0017]

[0018] Where r is the radius of the circular antenna array, c is the speed of light, and f is the frequency;

[0019] 2) The signal x received by the circular antenna array is:

[0020]

[0021] Among them, l represents the path number, θ l is the azimuth of the path, β l is the amplitude, s l is the received signal, n is the noise;

[0022] 3) When the received signal passes through the p+P+1th phase shifter, it will be moved to the Bessel space. At this time, the expression of the signal is:

[0023] Among them, n ′ For noise, is the Bessel function component;

[0024]

[0025] Among them J z (x) is a first-order Bessel function with z as base and x as variable;

[0026] 4) According to the generalized convergence characteristics of the Bessel function, when z is greater than x, J z (x) can be ignored, so when When , the RF link signal is expressed as:

[0027]

[0028] Among them, f max Indicates the highest frequency within the system bandwidth;

[0029] 5) The number of the radio frequency links is:

[0030]

[0031] The digital baseband processor is used to eliminate the frequency-related Bessel function components in the signal of the radio frequency link.

[0032] Set the parameters of the digital baseband processor to After the signal passes through the digital baseband processor, the signal is expressed as:

[0033]

[0034] Where n″ is the noise.

[0035] The spatial azimuth angle measurement method of the novel broadband circular antenna hybrid front-end device comprises the following steps:

[0036] Step 1: Construct a received signal dataset Z processed by the hybrid front-end device:

[0037] Step 2: Perform singular value decomposition on the data set signal Z:

[0038] Z=U∑V *

[0039] Step 3: Perform spatial division on the decomposed orthogonal input basis vectors according to the number of azimuth angles to be measured to obtain the signal space vectors of the received signal;

[0040] Step 4: Group the signal space vectors;

[0041] Step 5: Based on the recursive characteristics of the phase between the output signals of the hybrid front-end device, the spatial azimuth angle θ is calculated using the grouped signal space vector l Make an estimated calculation.

[0042] The above received signal data set Z is:

[0043] Where T is the number of sampling times; the element z in Z p+P+1,t represents the signal obtained by the tth sampling;

[0044] The singular value decomposition formula is:

[0045] Z=U∑V *

[0046] Where U and V are unitary matrices and Σ is a diagonal matrix.

[0047] The vertical spatial azimuth angle measurement method of the novel broadband circular antenna hybrid front-end device is realized by superimposing a plurality of the circular antenna hybrid front-end devices and adding a beam controller in each circular antenna hybrid front-end device to simultaneously estimate and measure the horizontal and vertical azimuth angles; specifically:

[0048] The beam controller is added between the RF link and the digital baseband processor to control the beam direction in the vertical direction so that each circular antenna hybrid front-end device receives incoming signals from different directions, thereby realizing the estimation and measurement of the vertical spatial azimuth.

[0049] The present invention has the following beneficial effects:

[0050] 1. In the novel broadband circular antenna hybrid front-end device of the present invention, the design of the radio frequency link is independent of the configuration of the communication system. Therefore, the front-end device of the present invention can be applied to a variety of communication scenarios;

[0051] 2. The novel broadband circular antenna hybrid front-end device of the present invention does not need to determine the frequency focus area for optimization when de-frequencying to adapt to the broadband communication system, thereby simplifying the calculation cost of the system;

[0052] 3. The fast azimuth angle measurement method of the hybrid front-end device designed by the present invention directly performs singular value decomposition on the collected signal data set, without the need for correlation operations, and with low calculation amount;

[0053] 4. The fast azimuth angle measurement method of the hybrid front-end device designed by the present invention uses the recursive characteristics of the phase between the data streams output by the hybrid front-end to quickly measure the spatial azimuth angle, thus overcoming the difficulty of angle measurement caused by the nonlinear phase relationship between the array response functions of the traditional circular array antenna. At the same time, this method does not require a global search for spatial angles, and is simple to implement and has low complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a schematic diagram of the circular antenna array structure in Embodiment 1 of the present invention;

[0055] Figure 2 It is a schematic diagram of the analog phase shift network structure in Embodiment 1 of the present invention and its full connection with each antenna array element;

[0056] Figure 3 is a schematic structural diagram of a circular antenna hybrid front-end device in Embodiment 1 of the present invention;

[0057] Figure 4 is the calculation result of the spatial azimuth in Embodiment 1 of the present invention;

[0058] Figure 5 is the computational complexity of the spatial azimuth angle measurement in Embodiment 1 of the present invention;

[0059] Figure 6 is a schematic diagram of the structure of a multi-layer circular antenna array in Embodiment 2 of the present invention;

[0060] Figure 7 is a schematic structural diagram of a multi-layer circular antenna hybrid front-end device in Embodiment 2 of the present invention;

[0061] Attached Figure 1-3 , 6-7 are marked as: 1-circular antenna array, 2-analog phase shifting network, 3-RF link, 4-digital baseband processor, 5-phase shifter, 6-adder, 7-beam controller. DETAILED DESCRIPTION

[0062] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0063] Embodiment 1:

[0064] In this embodiment 1, see Figures 1 to 3 A novel broadband circular antenna hybrid front-end device is mainly composed of a circular antenna array 1, an analog phase shift network 2, a radio frequency link 3 and a digital baseband processor 4.

[0065] Each array element of the circular antenna array 1 is connected to each phase shifter 5 in the analog phase shift network 2 in a fully connected manner, and the analog phase shift network 2 is connected to the digital baseband processor 4 via a radio frequency link 3 .

[0066] In this embodiment 1, see Figure 2 The analog phase shift network is mainly composed of a phase shifter 5 and an adder 6, and can be regarded as a network with a dimension of P′×N. Wherein, N is the number of elements of the circular antenna array, P′=(2P+1) is the number of the RF links, and P is the maximum dimension of the Bessel space.

[0067] The phase shifter 5 is connected to each element of the circular antenna array via a fully connected method. The connection method is based on an asymmetric discrete Fourier transform design and can be specifically expressed as:

[0068]

[0069] in

[0070] p=-P,-P+1,…,P

[0071] And n=1, 2, ..., N is the ordinal number of the circular antenna array.

[0072] In this embodiment 1, see Figure 3 , the number of radio frequency links 3 is determined using the generalized convergence property of the Bessel function, as follows:

[0073] 1) Assume that a(θ l ) is the array response function of the circular antenna array 1, which is a complex nonlinear function. The array response function expression of the nth array element is:

[0074]

[0075] Wherein, r is the radius of the circular antenna array 1, c is the speed of light, and f is the frequency.

[0076] 2) According to the above formula, the signal received by the circular antenna array 1 is:

[0077]

[0078] Among them, l represents the path number, θ l is the azimuth of the path, β l is the amplitude, s l is the received signal and n is the noise.

[0079] 3) When the received signal passes through the p+P+1th phase shifter, it will be moved to the Bessel space. At this time, the expression of the signal is:

[0080] in

[0081]

[0082] Among them J z (x) is a first-order Bessel function with base z and x as the variable.

[0083] 4) According to the generalized convergence characteristics of the Bessel function, when z is greater than x, J z (x) can be ignored, so when When , the RF link signal can be expressed as

[0084]

[0085] Among them, f max Indicates the highest frequency within the system bandwidth;

[0086] 5) The number of the radio frequency links 3 is:

[0087]

[0088] The digital baseband processor 4 is used to eliminate the Bessel function component related to the frequency in the signal of the radio frequency link. Set the parameters of digital baseband processor 4 to After the signal passes through the digital baseband processor, the signal can be expressed as:

[0089]

[0090] At this time, the phase component of the transmission signal is independent of the frequency, eliminating the beam deviation problem caused by frequency changes in the broadband communication system, so that the front-end device can be well applied to the broadband communication system.

[0091] In this embodiment 1, a method for quickly measuring the spatial azimuth using the novel broadband circular antenna hybrid front-end device of the present invention is also proposed, see Figures 1 to 3 , including the following steps:

[0092] Step 1: Construct a received signal data set processed by the hybrid front-end device:

[0093]

[0094] Where T is the number of sampling times, and the element z in Z p+P+1,t represents the signal obtained by the tth sampling;

[0095] Step 2: Directly perform singular value decomposition on the data set signal Z

[0096] Z=U∑V *

[0097] Where U and V are unitary matrices and Σ is a diagonal matrix.

[0098] Step 3: Perform spatial division on the decomposed orthogonal input basis vectors according to the number of azimuth angles to be measured to obtain the signal space vectors of the received signal.

[0099] Step 4: Group the signal space vectors.

[0100] Step 5: Based on the recursive characteristics of the phase between the output signals of the hybrid front-end device, the spatial azimuth angle θ is calculated using the grouped spatial vectors. l Get a quick estimate.

[0101] Figure 4 and Figure 5The simulation results of the mean square error and computational complexity of the spatial azimuth estimation method proposed in the present invention are shown respectively, and the comparison results of the method proposed in the present invention with the commonly used maximum likelihood estimation method and multiple signal classification method (Multiple Signal Classification, MUSIC) are shown. Figure 4 and Figure 5 It can be seen that the angle measurement accuracy of the method proposed in the present invention is significantly better than that of MUSIC but slightly inferior to that of the maximum likelihood estimation method. However, in terms of computational complexity, the method proposed in the present invention is much lower than that of MUSIC and the maximum likelihood estimation method. Therefore, it can be concluded that the method proposed in the present invention can quickly achieve high-precision estimation of the spatial azimuth.

[0102] Embodiment 2:

[0103] This embodiment is basically the same as Embodiment 1, except that:

[0104] In this embodiment 1, see Figures 6-7 , by superimposing multiple circular antenna hybrid front-end devices and adding a beam controller 7 in each circular antenna hybrid front-end device, simultaneous estimation of horizontal and vertical azimuth angles can be achieved.

[0105] Specifically, by adding a beam controller 7 of the hybrid front-end device between the RF link 3 and the digital baseband processor 4, the beam direction control in the vertical direction can be achieved, so that each circular antenna hybrid front-end device receives incoming signals from different directions, thereby realizing the measurement of the vertical space azimuth.

[0106] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A new broadband circular antenna hybrid front-end device, It is characterized in that Includes circular antenna array, analog phase shift network, RF link and digital baseband processor; Each array element in the circular antenna array is connected to each phase shifter in the analog phase shift network in a fully connected manner; The analog phase shift network is connected to the digital baseband processor via the radio frequency link; The analog phase shift network is a network with a dimension of P′×N, including a phase shifter and an adder; wherein N is the number of array elements of the circular antenna array, P′=(2P+1) is the number of the radio frequency links, and P is the maximum dimension of the Bessel space; The phase shifter is connected to each array element in the circular antenna array via a fully connected manner. The connection manner is based on an asymmetric discrete Fourier transform design. The phase shifter connection manner is specifically expressed as follows: Where p = -P, -P+1, ..., P, and n = 1, 2, ..., N, is the number of elements in the circular antenna array; The number of radio frequency links is determined using the generalized convergence characteristics of the Bessel function in the following manner: 1) Assume that a(θ l ) is the array response function of the circular antenna array, and the array response function expression of the nth array element is: Where r is the radius of the circular antenna array, c is the speed of light, and f is the frequency; 2) The signal x received by the circular antenna array is: Among them, l represents the path ordinal number, θ l is the azimuth of the path, β l is the amplitude, s l is the received signal, n is the noise; 3) When the received signal passes through the p+P+1th phase shifter, it will be moved to the Bessel space. At this time, the expression of the signal is: Among them, n ′ For noise, is the Bessel function component; b p+P+1 Indicates the connection mode of the phase shifter; Among them J z (x) is a first-order Bessel function with z as base and x as variable; 4) According to the generalized convergence characteristics of the Bessel function, when z is greater than x, J z (x) can be ignored, so when When , the RF link signal is expressed as: Among them, f max Indicates the highest frequency within the system bandwidth; 5) The number of the radio frequency links is: in Indicates rounding down; The digital baseband processor is used to eliminate the frequency-related Bessel function components in the signal of the radio frequency link. Set the parameters of the digital baseband processor to After the signal passes through the digital baseband processor, the signal is expressed as: Where n″ is the noise.

2. Based on the spatial azimuth angle measurement method of the novel broadband circular antenna hybrid front-end device described in claim 1, It is characterized in that The steps include: Step 1: Construct a received signal dataset Z processed by the hybrid front-end device: Step 2: Perform singular value decomposition on the data set signal Z: Step 3: Perform spatial division on the decomposed orthogonal input basis vectors according to the number of azimuth angles to be measured to obtain the signal space vectors of the received signal; Step 4: Group the signal space vectors; Step 5: Based on the recursive characteristics of the phase between the output signals of the hybrid front-end device, the spatial azimuth angle θ is calculated using the grouped signal space vector l Make an estimated calculation.

3. The spatial azimuth angle calculation method of the novel broadband circular antenna hybrid front-end device according to claim 2, It is characterized in that The received signal data set Z is: Where T is the number of sampling times; the element z in Z p+P+1,t represents the signal obtained by the tth sampling; The singular value decomposition formula is: Z=U∑V * Where U and V are unitary matrices and Σ is a diagonal matrix.

4. Based on the vertical spatial azimuth angle measurement method of the novel broadband circular antenna hybrid front-end device described in claim 1, It is characterized in that By superimposing a plurality of the circular antenna hybrid front-end devices and adding a beam controller in each circular antenna hybrid front-end device, simultaneous estimation and measurement of the horizontal and vertical azimuth angles can be achieved; specifically: The beam controller is added between the RF link and the digital baseband processor to control the beam direction in the vertical direction so that each circular antenna hybrid front-end device receives incoming signals from different directions, thereby realizing the estimation and measurement of the vertical spatial azimuth.

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